WASHINGTON (Reuters) – U.S. President Donald Trump said on Monday he wants to deport some violent criminals who are U.S. citizens to El Salvador, where they would be incarcerated under an agreement with that country’s government.

Trump’s spoke to journalists at the White House during the state visit of Salvadoran President Nayib Bukele.

The remarks were one of the clearest signals yet that the U.S. president is serious about deporting naturalized and U.S.-born citizens, a proposal that has alarmed civil rights advocates and is viewed by many legal scholars as unconstitutional.

Trump said he would only go through with the idea if his administration determined it was legal. It was not clear what level of due process an American would receive before being deported.

“We always have to obey the laws, but we also have homegrown criminals that push people into subways, that hit elderly ladies on the back of the head with a baseball bat when they’re not looking, that are absolute monsters,” Trump said.

“I’d like to include them in the group of people to get them out of the country, but you’ll have to be looking at the laws on that.”

Trump Told Reporters He ‘Loved’ Idea of Deporting Citizens

Trump told reporters last week that he “loved” the idea of deporting citizens to El Salvador, after Bukele said the country was open to housing U.S. prisoners.

White House press secretary Karoline Leavitt later confirmed that the proposal was on the table, saying Trump had “simply floated” the idea.

The Trump administration has sent hundreds of migrants accused of criminal affiliations to El Salvador’s harsh mega-prison known as the Terrorism Confinement Center, under often-contested legal authorities. The U.S. is paying El Salvador $6 million.

The highest-profile deportee, Kilmar Abrego Garcia, a Salvadoran national, was deported despite a judicial order protecting him from removal. The U.S. government has described his deportation as an administrative error.

The U.S. Supreme Court last week upheld a lower court ruling directing the administration to “facilitate and effectuate” his return. But it said the term “effectuate” was unclear and might exceed the authority of the district court judge.

In a court filing on Sunday, the administration said it was not obligated to help Abrego Garcia get out of prison in El Salvador. Bukele said during the Monday meeting with Trump that he would neither return Abrego Garcia nor release him in El Salvador, and Trump said he was not interested in asking for Abrego Garcia back.

(Reporting by Gram Slattery and Sarah Morland; Editing by Colleen Jenkins and Cynthia Osterman)